People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
Same as Silver Scales, but in black. Turn your site into a dragon with this great scale pattern.
Source Alex Parker
Nasty or not, it’s a nice pattern that tiles. Like they all do.
Source Badhon Ebrahim
Prismatic Polka Dots Mark II 2 No Background
Source GDJ
A grid of squares with green colours. Since the colours are randomly distributed it is automatically seamless.
Source Firkin
This pack of filters can help you adding a blocky overlay to objects. May come handy at drawing blocks of stone.
Source Lazur URH
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
I asked Gjermund if he could make a pattern for us – result!
Source Gjermund Gustavsen
Remixed from a drawing in 'The Canadian horticulturist', 1892
Source Firkin
Inspired by the B&O Play, I had to make this pattern.
Source Atle Mo
This is the remix of "Background pattern 115" uploaded by "Firkin".Thanks.
Source Yamachem
Bigger is better, right? So here you have some large carbon fiber.
Source Factorio.us Collective
It has waves, so make sure you don’t get sea sickness.
Source CoolPatterns
From a drawing in 'Hubert Montreuil, or the Huguenot and the Dragoon', Francisca Ouvry, 1873.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
You can never get enough of these tiny pixel patterns with sharp lines.
Source Designova
A blue background wallpaper for websites. It has a seamless texture with vertical stripes. It looks quite nice not only when using as a tiled background on websites, but also on computer desktops.
Source V. Hartikainen
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin